Re: [RFC][PATCH v2 4/4] vfs: wrap write f_ops with file_{start,end}_write()
From: Jan Kara <jack@suse.cz>
Date: 2017-01-24 10:09:55
Also in:
linux-fsdevel
On Mon 23-01-17 21:43:16, Amir Goldstein wrote:
Before calling write f_ops, call file_start_write() instead
of sb_start_write().
This ensures freeze protection for both overlay and upper fs
when file is open from an overlayfs mount.
Replace {sb,file}_start_write() for {copy,clone}_file_range() and
for fallocate().
For dedup_file_range() there is no need for mnt_want_write_file().
File is already open for write, so we already have mnt_want_write()
and we only need file_start_write().
Signed-off-by: Amir Goldstein <amir73il@gmail.com>The patch looks like a good cleanup regardless of your overlayfs work. It seems we just missed these places when converting freeze protection to file_start_write(). You can add: Reviewed-by: Jan Kara <jack@suse.cz> Honza
quoted hunk ↗ jump to hunk
--- fs/open.c | 4 ++-- fs/read_write.c | 12 ++++-------- include/linux/fs.h | 26 +++++++++++++------------- 3 files changed, 19 insertions(+), 23 deletions(-)diff --git a/fs/open.c b/fs/open.c index 9921f70..d3fe1a1 100644 --- a/fs/open.c +++ b/fs/open.c@@ -316,7 +316,7 @@ int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len) if (!file->f_op->fallocate) return -EOPNOTSUPP; - sb_start_write(inode->i_sb); + file_start_write(file); ret = file->f_op->fallocate(file, mode, offset, len); /*@@ -329,7 +329,7 @@ int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len) if (ret == 0) fsnotify_modify(file); - sb_end_write(inode->i_sb); + file_end_write(file); return ret; } EXPORT_SYMBOL_GPL(vfs_fallocate);diff --git a/fs/read_write.c b/fs/read_write.c index 5816d4c..1e42487 100644 --- a/fs/read_write.c +++ b/fs/read_write.c@@ -1538,7 +1538,7 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, if (len == 0) return 0; - sb_start_write(inode_out->i_sb); + file_start_write(file_out); /* * Try cloning first, this is supported by more file systems, and@@ -1574,7 +1574,7 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, inc_syscr(current); inc_syscw(current); - sb_end_write(inode_out->i_sb); + file_end_write(file_out); return ret; }@@ -1976,11 +1976,7 @@ int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same) } dst = file_inode(dst_file); - ret = mnt_want_write_file(dst_file); - if (ret) { - info->status = ret; - goto next_loop; - } + file_start_write(dst_file); dst_off = info->dest_offset; ret = clone_verify_area(dst_file, dst_off, len, true);@@ -2013,7 +2009,7 @@ int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same) } next_file: - mnt_drop_write_file(dst_file); + file_end_write(dst_file); next_loop: fdput(dst_fd);diff --git a/include/linux/fs.h b/include/linux/fs.h index 71811be..8a4dbc6 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h@@ -1741,19 +1741,6 @@ extern int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff, extern int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same); -static inline int do_clone_file_range(struct file *file_in, loff_t pos_in, - struct file *file_out, loff_t pos_out, - u64 len) -{ - int ret; - - sb_start_write(file_inode(file_out)->i_sb); - ret = vfs_clone_file_range(file_in, pos_in, file_out, pos_out, len); - sb_end_write(file_inode(file_out)->i_sb); - - return ret; -} - struct super_operations { struct inode *(*alloc_inode)(struct super_block *sb); void (*destroy_inode)(struct inode *);@@ -2579,6 +2566,19 @@ static inline void file_end_write(struct file *file) __sb_end_write(locks_inode(file)->i_sb, SB_FREEZE_WRITE); } +static inline int do_clone_file_range(struct file *file_in, loff_t pos_in, + struct file *file_out, loff_t pos_out, + u64 len) +{ + int ret; + + file_start_write(file_out); + ret = vfs_clone_file_range(file_in, pos_in, file_out, pos_out, len); + file_end_write(file_out); + + return ret; +} + /* * get_write_access() gets write permission for a file. * put_write_access() releases this write permission.-- 2.7.4
-- Jan Kara [off-list ref] SUSE Labs, CR